Heat exchangers



Sept. 27, 1960 .c. PELLEGRINI HEAT EXCHANGERS 2 Sheets-Sheet 1 Filed Feb. 24, 1958 F/ql A, Arrf SePt- 27 1960 l.. c. PELLEGRINI 2,954,213

HEAT EXCHANGERS Sheets-Sheet 2 FiledA Feb. 24, 1958 :N /m/E/vroe ou/J C PELLfcae//v/ HEAT EXCHANGERS Louis C. Pellegrini, St. Louis, Mo., assiguor to Marlo Coil Company, St. Louis, Mo., a corporation of Missoun Filed Feb. 24, 1958, Ser. No. 717,060

6 Claims. (Cl. 257-255) This invention relates to improvements in heat exchangers. More particularly, this invention relates to improvements in heat exchangers that utilize a heatexchanging medium which can freeze.

It is therefore an object of the present invention to provide an improved heat exchanger that utilizes a heatexchanging medium which can freeze. Y

In the operation of heat exchangers that utilize a heatexchanging medium which can freeze, it is necessary either to keep the heat exchangers above the freezing temperature of the heat-exchanging medium or to completely drain those heat exchangers. Failure to do one or the other of those things can lead to freezing of the heat-exchanging medium and to bursting of one or more portions of the heat exchangers. Where the heat exchangers are located in spaces subject to freezing tempera- States kPaident ice permit them to be drained. The connections between the lowermost ends of the passages and the rst said header and the communication between the intermediate openings and the other headers make sure that the heatexchanging medium has every opportunity to drain out o=f the heat exchanger whenever that heat exchanger is to 'be drained. Lt is therefore an object of the present invention to provide `a heat exchanger wherein all of the individual passages vhave their lowermost ends connected to a header that has a drain plug and wherein most of the passages have openings intermediate their ends that communicate lwith other headers equipped with drain plugs.

The intermediate openings that communicate with the other headers are so located that the pressures on the heat-exchanging mediums lat all of the openings communicating with any one header are substantially the same. As a result, there is little or no tendency for the tures or are installed in buildings that are unheated durn ing cold weather, the cost of keeping those heat exchangers labove the freezing temperature of the heatexchanging medium can be excessive. Consequently it is standard practice to drain heat exchangers, in unheated buildings, of any heat-exchanging medium that could freeze.

Theoretically it should be a simple matter to drain a heat exchanger, `consisting of a number of tubes that extend through and are supported by heat-exchanging fins, by disconnecting its ends or by providing drain plugs or cocks at its ends. In practice, however, it has been found that such a heat exchanger does not always drain sufliciently to protect it from injury due to freezing of the heat-exchanging medium. In some instances the heat exchanger gets canted so part of the heat-exchanging medium is trapped and can not kdrain out, but regardless of the reason, the heat exchanger is subject to injury if all of the heat exchanging medium does not drain out. The present invention avoids any such injury by providheat-exchanging medium to bypass any of the passages. Hence the present invention facilitates full draining of the heat exchanger while assuring full use of the heatv exchanging area of all of the passages. It is therefore an object of the present invention to locate intermediate openings in the passages in a heat exchanger so the pressures on the heat-exchanging medium at all openings communicating `with the same header are substantially equal.

Other and further objects and advantages of the present invention should become apparent from an examination of the dnawing and accompanying description,

In the drawing and accompanying description, a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that the invention will be defined by the appended claims.

In the drawing, Fig. l is a plan View of a heat exchanger that is made in accordance with the principles and ing a heat exchanger, consisting of a number of tubes that extend through and are supported by heat-exchanging tins, that is able to permit all of the heat-exchanging medium to drain out. It is therefore an object of the present invention to provide a heat exchanger, consisting of tubes that extend through and are supported by heatexchanging fins, that is able to permit all of the heatexchanging medium to drain out.

The heat exchanger provided by the present invention consists of a number of U-shaped tubes that are interconnected and that extend through and are supported by heat-exchanging ns; and each of those tubes has its arms generally horizontal with one arm above the level of the other. The U-shaped tubes are interconnected in such a way that they define a number of individual passages for the heat-exchanging medium; and each passage has the generally horizontal portions thereof at different levels and connected by inclined portions. The lowermost end of each passage is connected to a header that has a drain plug to permit it to be drained; and most of the passages have openings, intermediate their ends, that communicate with other headers that have drain plugs to teachings of the present'invention,

Fig. 2 is a side elevational view of the heat exchanger shown in Fig. l,

Fig. 3 is an end elevational view of the heat exchanger shown in Figs. l and 2,

Fig. 4 is a sectional view in plan through a portion of the heat exchanger shown in Figs. l-3, and it is taken along the plane indicated by the lines 4--4 in Fig. 3, and

Fig. 5 is a sectional View in elevation of a portion of the heat exchanger shown in Figs. 1 3, and it is taken along the plane indicated by the lines 5-5 in Fig. 4.

g yReferring to the drawing in detail, the numeral 20denotes the frame of a heat exchanger that is made in accordance with the principles and teachings of the present invention. That frame is generally rectangular in elevation, and it will usually be made from metal channels that are suitably connected together. The frame 20 supports a number of parallel closely adjacent fins 40, and those ns are mounted in the frame 20` in the standard and usual way. v

The tins 4t) are suitably perforated to accommodate the arms of a number of U-shaped tubes; thosearms extending through and being supported within alined openings in the fins. As indicated particularly by Fig. 3, the heat exchanger shown inthe drawing has six rows of tubes; and the two right-handmost rows are formed by the upper and lower arms of the U-shaped tubes 22, 24,V

26, 28, 30, 32, 34, 36 and 38. The two centermost rows of tubes are defined by the upper and lower arms of the U-shaped tubes 42, 44, 46, 48, 50, 52., 54, 56 and 58. The two left-handmost rows of tubes are formed by the upper and lower arms of the U-shaped tubes 60, 62, 64, 66, 68, 70,72, '74 and 76. As shown particularly by Figs. l and 2, all of the U-shaped tubes are mounted in the fins 40 so the closed ends of those tubes are at the left-hand sides of Figs. l and 2. However, it will be understood that this invention is also applicable to heat exchangers that do not use iins.

The free ends of the lower arms `of the U-shaped .tubes 22, 24, 26, '28, '30, 32, 34, '36 and -38 extend to, and are connected with, openings in a vertical header "78 which constitutes the supply header of the heat exchanger. A large diameter horizontal tube 80 is connected to the lower end of the header 78, and that tube supplies the header 78 with the heat-exchanging medium. An air vent plug 82 is seated in a suitable opening at the top of the header 78, and a drain plug 84 is seated in a suitable opening at the bottom of that header. When the header is to be drained, the plugs 82 and 84 are removed; and that is simply and easily done. The free ends of the upper arms of the U-shaped tubes 22, 24, 26, 28, 311, 32, 34, 36 and 38 extend through and project beyond openings at the opposite sides of a vertical header 86. The header 86 has an air vent plug 88 seated in a suitable opening at the top thereof and has a drain plug 99 seated in a suitable opening at the bottom thereof. Openings, not shown, similar to the openings 148 and 149 in Figs. 4 and 5 are provided in the free ends of the upper arms of the U- shaped tubes 22, 24, 26, 28, 38, 32, 34, 36 and 38; and those openings are enclosed within and surrounded by the header 86. The openings corresponding to the openings 148 are vent openings, and the openings corresponding to the openings 149 are drain openings.

A number of U-shaped bends 118, 112, 114, 116, 118, 128, 122 and 124 extend between, and are connected to, the free ends ofthe upper arms of the U-shaped tubes 24, 26, 28, .30, 32, 34, 36 and 38 and the free ends of the lower arms of the U-shaped tubes 42, 44, 46, 48, 541, 52, S4 and 56. The free ends of the upper arms of the U-shaped tubes 42, 44, 46, 48, 50, 52, 54, 56 and 58 extend through and project beyond openings at the opposite sides of a vertical header 92 that is similar to the header 86. An air vent plug 94 is seated in a suitable opening at the top of that header, and a drain plug 96 is seated in a suitable opening at the bottom of that header. The free ends of the upper arms of each of the U-shaped tubes 42, 44, 46, 48, 58, 52, 54, 56 and 58 have openings 148 and 149, as indicated by Figs. 4 and 5. Those openings are enclosed and confined by the header 92.

A number of U-shaped bends 132, 134, 136, 138, 140, 142, 144 and 146 extend between, and are connected to, the free ends of the upper arms of the U-shaped tubes 44, 46, 48, 54B, f2, 54, 56 and 58 and the lower arms of the U-shaped tubes 68, 62, 64, 66, 68, 78, 72 and '74. The free ends of the upper arms of the lJ-shaped tubes 69, 62, 64, 66, 68, 70, 72, 74 and 76 extend to, and are connected with, openings in a vertical header 98; and that header serves as the return header for the heat exchanger. The header 98 is substantially as large as the header 78, and it has an air vent plug 188 seated in a suitable opening at the top thereof and it has a drain plug 162 seated in a suitable opening at the bottom thereof.

The numeral 106 denotes a generally J-shaped tube which is connected to the free end of the upper arm of the U-shaped tube 22 and which extends to, and is connected with, an opening at the right-hand side of the header 98, as that header is viewed in Fig. 3. That J- shaped tube conducts the heat-exchanging medium introduced into tube 22 to the return header 98. A short. straight tube 130 extends from the free end of the upper arm of the tube 42 to, and connects with, the tube 186. The tube 130 coacts with the tube 186 to conduct the heat-exchanging medium from the tubes 24 and 42 to the return header 98.

A generally J-shaped tube 126 extends from an opening in the left-hand side of the header 78, as that header is viewed in Fig. 3, to, and connects with, the free end of the lower arm of the U-shaped tube 76. The tube 126 serves to conduct heat-exchanging medium from header 78 tothe U-shaped tube 76. A short, straight tube 128 extends from the straight portion of the J-shaped tube 126 to the projecting end of the lower arm of the U-shaped tube S8. The tubes 126 and 128 coact to conduct heatexchanging medium from the header 78 to the U-shaped tube 58.

The various U-shaped tubes, the U-shaped bends, the two J-shaped tubes, and -the short, straight connecting tubes provide a series of individual passages between the supply header 78 .and the .return header 98. Those separate passages are as follows: U-shaped tube 22 and J- shaped tube 186; U-shaped tube 24, U-s'haped bend 118', U-shaped tube 42, connecting tube 138 and J-shaped tube 106; U-shaped tube v26, ViJ-shaped bend 112, U-shaped tube 44, U-shaped bend 132 and U-shaped tube 60; U- shaped tube 28, -U-sh'aped bend 114, -U-shaped tube 46, U-shaped bend 1'34 and U-shaped tube 62; U-shaped tube 38, U-shaped bend 116, U-shaped tube 48, U-shaped bend 136 and U-shaped tube 64; U-shaped tube 32, U-shaped bend 118, U-shaped tube 5t), U-shaped bend 138 and U- shaped tube 66; U-shaped tube 34, U-shaped bend 128, U-shaped tube 52, yU-shaped bend 140 and U-shaped tube 68; U-shaped tube 36, U-shaped bend 122, U-shaped tube 54, U-shaped bend 142 and U-shaped tube 78; U-shaped tube 38, U-shaped bend l124, U-shaped tube 56, U-shaped bend 144 and U-shaped tube 72; J-shaped tube 126, lconnecting tube `128, U-shaped tube 58, U-shaped bend 146 and U-shaped tube 74; and J-shaped tube 126 and U- shaped tube 76. These passages will conduct heat-exchanging medium from the supply header 78 to the return header 98; and as they do so they will either transfer vheat to that heat-exchanging medium and absorb heat from the air passing over the heat exchanger, or they will absorb heat from that heat-exchanging medium and transfer that heat -to the air passing over the heat exchanger. The passages Will transfer heat to the heat-exchanging medium where that vheat-exchanging medium is chilled water, and will absorb heat from the heat-exchanging medium where that heat-exchanging medium is hot water.

With the exception of the short passage consisting of J-shaped tube 126 and U-shaped tube 76, each of the passages has its lower end connected, directly or indirectly, Vto the supply header 718 and has openings 148 and 149 intermediate its ends. The heat exchanger will be mounted so the right-hand end thereof, as that heat exchanger isviewed in Fig. 2, is slightly lower than the left-hand end thereof. This can be accomplished eitherv by giving appropriate instructions to the installer, by making the frame 20 so it cants the tubes whenever it is levelled, or both. Consequently, when `it is desired to drain that heat exchanger, all of the heat-exchanging medium will dow to the free ends of the lower arms of the U-shaped tubes and thence to the header 78 or to the headers 86 and 92. As a result, the removal of the vent and drain plugs 82, 88, 94 and 188 and 84, 90, 96 and 192 respectively, will assure full draining of the heat exchanger.

The heat-exchanging medium adjacent the openings 148 and 149 at the free ends of the upper arms of the U-shaped tubes 22, 24, 26, 28, 38, 32, 34, 36 and 38 will be under substantially the same pressures, therefore there will be little or no tendency for any part of the heatexchanging medium to flow from the upper arm of anyone of those tubes and enter the upper arm of other of those tubes. Similarly, the heat-exchanging medium adjacent the openings 148 and 149 in the `free ends of the upper arms of the U-shaped tubes 42, 44, 46, 48, 551, 52, 54, 56 and 58 Will be under substantially the same pressures; and there again there will be little or no tendency for the heat-exchanging medium to pass from the free ends of one of those VU-shaped tubes to the free ends of other of those U-shaped tubes. This assures full heat-exchanging efficiency for the heat exchanger while `also assuring fuil draining of that heat exchanger.

lf desired, valves or `cocks could be substituted for the ventplugs and drain plugs shown. While that substitution increases the cost, it makes it possible to locate those valves or cocks outside of the heat exchanger housing and ductwork, `and thereby facilitates draining of the heat exchanger. Also, if desired, the drain openings 149 in the various tubes can be made so large that the vent openings 148 are not needed. For example, the drain openings could be elongated transversely of the tubes to extend above the center lines of the tubes; or the drain openings could actually consist of spaces `between the ends of the U-shaped tubes and the U-shaped bends.

Whereas the drawing and accompanying description have shown and described a preferred embodiment of the present invention, it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I clairn is:

1. In a heat exchanging device that has a plurality of generally horizontal tubes disposed in horizontally spaced generally vertical rows, tubular connections that extend between and are connected to the ends of some of said tubes to form a plurality of continuous Vand uninterrupted passages for heat exchanging medium, a supply header connected to the inlet ends of said passages, and a return header connected to the outlet ends of said passages, the improvement which comprises drain openings in some of said passages intermediate the ends of said passages, a header encasing said drain openings, and a drain opening for the third said header.

2. In a heat exchanging device that has a plurality of generally horizontal tubes disposed in horizontally spaced generally vertical rows, tubular connections that extend between and are connected to the ends of some of said tubes to form a plurality of continuous and uninterrupted passages for heat exchanging medium, a supply header connected to the inlet ends of said passages, and a return header connected to the outlet ends of said passages, the improvement which comprises drain openings in some of said passages intermediate the ends of said passages, a header encasing said drain openings, -and a drain opening for the third said header, said passages inclining upwardly and rearwardly from one face of said heat exchanging device, the third said header beingadjacent one end of said heat exchanging device and being intermediate the planes dened by the said one face and the opposite face of said heat exchanging device.

3. In a heat exchanging `device that has a plurality of generally horizontal tubes disposed in horizontally spaced generally vertical rows, tubular connections that extend between and are connected -to the ends of some of said tubes to form a plurality of continuous and uninterrupted passages for heat exchanging medium, a supply header connected to the inlet ends of said passages, `and 'a return header connected to the outlet ends of said passages, the improvement which comprises drain openings in some of said passages intermediate the ends of said passages, a

I 6 header encasing said drain openings, and a drain opening for the third said header, said drain openings in said passages being in generally vertical alinernent, said third header being generally vertical.

4. In a heat exchanging device that has -a plurality of generally horizontal tubes disposed in horizontally spaced generally vertical rows, tubular connections that extend between and are connected to the ends of some of said tubes to form a plurality of continuous and uninterrupted passages for heat exchanging medium, a supply header connected to the inlet ends of said passages, and a return header connected to the outlet ends of said passages, the improvement which comprises a group of vertically alined drain openings in some of said passages, a second group of vertically alined drain openings in said passages, said drain openings being intermediate the ends of said passages, a third header encasing the rst said group of vertically alined drain openings, a fourth header encasing said second group of vertically alined drain openings, and drain openings for said third and fourth headers.

5. In a heat exchanging device that has a plurality of generally horizontal tubes disposed in horizontally spaced generally vertical rows, tubular connections that extend between and are connected to the ends of some of said tubes to form a plurality of continuous and uninterrupted passages for heat exchanging medium, a supply header connected to -the inlet ends of said passages, and a return header connected to the outlet ends of said passages, the improvement which comprises la group of vertically alined drain openings in some of said passages, a second group of vertically alined drain openings in said passages, said drain openings being intermediate the ends of said passages, a third header encasing the rst said group of vertically alined drain openings, a fourth header encasing said second group of vertically alined drain openings, and drain openings for said third and fourth headers.

6. In a heat exchanging device that has a plurality of generally horizontal tubes disposed in horizontally spaced generally vertical rows, tubular connections that extend between and are connected to the ends of some of said tubes to form a plurality of continuous and uninterrupted passages for heat exchanging medium, a supply header connected to the inlet ends of said passages, and a return header connected to the outlet ends of said passages, the improvement which comprises drain openings in some of said passages intermediate the ends of said passages, a header encasing said drain openings, and a drain opening for the third said header, said drain openings in said tubes being spaced from said supply header substantially the same distances whereby heat exchange medium at said openings are under substantially the same pressure.

References Cited in the le of this patent UNITED STATES PATENTS 2,301,433 McElgin Nov. 10, 1942 

